Electrical lighting units, commonly referred to as “luminaires,” are used in various types of indoor and outdoor lighting applications. “Low bay” indoor applications generally include mounting lighting units at heights of approximately 20 feet or less, whereas “high bay” indoor applications generally include mounting lighting units at ceiling heights of approximately 20 to 45 feet, or sometimes higher. Conventional lighting units for high bay and low bay applications generally include a light housing that is suspended from a ceiling structure and houses a light source, and a generally conical or bell-shaped refractor that depends downwardly from the light housing and directs light produced by the light source.
In many lighting applications, it is desirable to provide a sensor for detecting a local condition (e.g., motion, light, etc.) in a region surrounding the lighting system, and causing the lighting system to energize one or more of the individual lighting units only in response to detection of the condition by the sensor. In this manner, energy is substantially conserved by ensuring that lighting units are energized only when appropriate. In conventional lighting systems, such sensors are mounted remotely from the lighting units. While attempts have been made to mount sensors directly to the lighting units, in such designs the sensors undesirably block at least some of the light produced by the lighting units.
Accordingly, there is a need for improvements to known lighting systems to address at least the drawbacks discussed above.